The present invention is in the area of electric power distribution, and has particular application to power distribution for rack-mounted electronic systems.
Power distribution systems in current art exist for routing and/or converting AC or DC power to devices or systems in a wide variety of situations, and have been the subject of considerable research and development. A variety of power distribution systems have been developed to power systems and devices in many different applications that vary greatly in voltage, wattage, design and sophistication, depending on the power requirements and other specific requirements of the application. For example, in some applications the systems or devices powered by the distribution system are allowed to completely power down during repair or upgrade of the power distribution system itself, or any component of the system, while other applications may require that the powered systems or devices remain at least partially powered on and functioning during such events.
In critical applications such as systems for routing or switching data packets on the Internet, the computer equipment and devices require constant and consistent power to be supplied at all times to allow for continuous and extended operation under all power conditions, maintaining a high degree of operating reliability for data or process security.
Uninterruptible and redundant power distribution systems have been incorporated to achieve this xe2x80x9calways-onxe2x80x9d feature. Such systems, through such as parallel connection and operation, allow for repair or replacement of some part of the power system without disrupting the power distributed. It is in this critical environment that embodiments of the present invention are used.
Such power distribution systems are used with Internet routing equipment of various size and capacity, ranging from small desktop pedestal units, to mid and upper-range routing systems. Components of the power distribution system are sometimes contained within the chassis of the router, often accessible from the back of the chassis, as in the case of a pedestal unit. However, with current and probable future growth of network traffic over the Internet, it is desirable for many Internet routing equipment users to be capable of long-term traffic-handling capacity growth and extremely high availability of the routing equipment, expandable (scalable) in accordance with demand.
In order for Internet routing service providers to respond to growing traffic-handling needs and to achieve gigabit and terabit-per-second data-handling performance, multi-chassis, scalable router designs are being incorporated, allowing installation of additional modular components. The scalable chassis, commonly referred to as a rack chassis in the art, also incorporates a scalable circuit breaker and power distribution system in order to adequately serve the additional power requirements of added (scaled-up) circuitry. A scalable circuit breaker system typically comprises a plurality of removable breaker boxes modularly mounted in separate slots or assemblies within the rack chassis, which is often the same chassis containing the modular units comprising the cards and other components of the router. The combination of breaker boxes has the primary function of protecting the router components in the case of a power surge or overload, and during such an event, continues to distribute uninterrupted power to conductors distributing power elsewhere in the router.
In such a system separate breaker modules are connected in parallel to points on the incoming and outgoing power carrier so that one of a pair of breaker modules in a live power distribution system can be removed for repair or upgrade, for example, while the remaining connected module continues to supply constant and interrupted power to the components of the router. Hot-swapping, as it is known in the art, is a frequently practiced method of module removal and insertion in many different systems were constant power delivery is critical.
The components of a large, scalable Internet router as described herein typically operate at DC voltage that is commonly supplied to the breaker modules of the scalable router by a battery room which converts the primary power of the host facility to DC power. The converted DC power is supplied to the breaker modules at low voltage and high amperage level depending on the power requirements. The rack-mounted breaker modules utilize standard breaker switches for circuit protection, and additional safeguards are often incorporated in such power systems to maintain reliability and availability of the power, as well as to minimize electrical hazards.
In an extremely critical environment such as for Internet data routing as described above, system up time must be maximized, and any malfunction or anomaly within the routing equipment or power distribution system must be quickly identified and rectified. For a technician or worker remotely monitoring the operation of the circuit breaker system for large scalable Internet router, for example, it is particularly important for all of the monitored data of circuit breaker operating status to be complete and accurate. One problem inherent with large and complex systems with remote monitoring or control capability such as described above, is that, should a failure or malfunction occur in the monitoring card or any of the connections between it and the circuit breakers, the reliability of the data send for monitoring is compromised, and a false indication may be given. Additionally, determination of the cause of a problem indicated by the monitor, such as low voltage in a circuit breaker, for example, may not actually be true, but instead a malfunction within the monitoring card causing a false reading. In such a circuit breaker monitoring system with centralized intelligence on a monitoring card, such as is common in current art, it can be difficult for a worker or technician to accurately determine if the reported problem is real and has a real cause, or is misrepresented by a faulty monitoring card. Such a monitoring system decreases in reliability and dependability as the size and complexity of the system increases. As the number of line and fabric card modules, for example, installed in the rack chassis increases, the number of circuit breaker modules and related connections to the monitoring card also increases, having a further detrimental effect on the reliability of the data sent by the monitoring card.
What is clearly needed, is an improved method and apparatus for protecting circuits in a scalable modular chassis that provides reliable intelligence for remote monitoring of basic status and functions of the circuit breaker system, while supplying highly reliable, redundant power output for distribution to other parts of the host system.
In a preferred embodiment of the present invention a replaceable circuit breaker module is provided, comprising a housing for supporting and enclosing elements of the module, a circuit breaker mounted in the housing in a manner that an action of installing the module connects the breaker to bridge an incoming and an outgoing conductor, and monitoring circuitry for monitoring characteristics of the circuit breaker, the monitoring circuitry mounted in the housing and having a first connector element for engaging a mating connector element in the action of installing the module. The module is characterized in that action of withdrawing the circuit breaker module also withdraws the monitoring circuitry.
In preferred embodiments the monitoring circuitry includes sensors for monitoring one or more of breaker presence, on/off state of the breaker, and voltage provided to the breaker. Also in some embodiments the module is configured as a docking module for docking in a bay of a cabinet to be powered, and the installation action is an action of docking the module in the docking bay.
In some embodiments there is a safety mechanism for preventing the module from being docked or withdrawn with the breaker on. The safety mechanism may comprise a horizontal bar guided vertically in slots such that the bar is held in a notch of a bracket affixed to a cabinet to be powered when the breaker is closed (on), and lowering the bar from the notch to release the module for extraction trips the breaker open (off), thus preventing arcing during docking or withdrawing of the module.
In another aspect of the invention an electronic cabinet having a redundant power supply is provided, comprising a redundant power unit having docking bays for two or more breaker modules, a first conductor delivering power to the power unit from an external source, and a second conductor delivering power from the power unit to elements in the cabinet from the power unit. Each breaker module comprises a housing for supporting and enclosing elements of the module, a circuit breaker mounted in the housing in a manner that an action of installing the module connects the breaker to bridge first and the second conductors, and monitoring circuitry for monitoring characteristics of the circuit breaker, the monitoring circuitry mounted in the housing and having a first connector element for engaging a mating connector element in the action of installing the module, such that action of withdrawing the circuit breaker module also withdraws the monitoring circuitry.
In some embodiments of the cabinet the monitoring circuitry includes sensors for monitoring one or more of breaker presence, on/off state of the breaker, and voltage provided to the breaker. Also in some embodiments the module is configured as a docking module for docking in a bay of a cabinet to be powered, and the installation action is an action of docking the module in the docking bay.
In some embodiments the cabinet further comprises a safety mechanism preventing the module from being docked or withdrawn with the breaker on. The safety mechanism may be a horizontal bar guided vertically in slots such that the bar is held in a notch of a bracket affixed to a cabinet to be powered when the breaker is closed (on), and lowering the bar from the notch to release the module for extraction trips the breaker open (off), thus preventing arcing during docking or withdrawing of the module. The cabinet may be dedicated to a packet router in the Internet.
In yet another aspect of the invention a method for improving reliability of a redundant breaker system for an electronic cabinet is provided, comprising the steps of (a) providing two or more breaker modules configured, when installed, to bridge the same two power buses; and (b) providing breaker monitoring circuitry with each of the two or more breaker modules, the monitoring circuitry configured to be removed and replaced with the breaker modules, such that monitoring circuitry is replaced whenever a breaker module is replaced.
In some embodiments of the method the monitoring circuitry includes sensors for monitoring one or more of breaker presence, on/off state of the breaker, and voltage provided to the breaker. Also in some embodiments the modules are configured as docking modules for docking in bays of the cabinet to be powered, and the installation action is an action of docking the module in the docking bay. In some cases the modules further comprise a safety mechanism preventing the modules from being docked or withdrawn with the breaker on. The safety mechanism may be a horizontal bar guided vertically in slots such that the bar is held in a notch of a bracket affixed to a cabinet to be powered when the breaker is closed (on), and lowering the bar from the notch to release the module for extraction trips the breaker open (off), thus preventing arcing during docking or withdrawing of the module.
In various embodiments of the present invention taught in enabling detail below, for the first time a breaker module is provided having built-in monitoring circuitry, such that the monitoring circuitry gets replaced whenever a module is replaced.